An aircraft, such as a rotorcraft, may be used to transport cargo or a payload to a destination. Slung load cargo may often contain sensitive equipment or may be subject to a maximum drop rate or impact force at the time of drop off. The cargo, or equipment contained therein, might not withstand excessive impact associated with gravitational forces. In autonomous cargo applications, such as in unmanned aerial vehicle (UAV) applications, the cargo is delivered and dropped autonomously by a UAV vertical takeoff and landing (VTOL) platform. In such a case, the UAV needs to sense the event of the cargo making contact with the ground in order to perform a safe and controlled detachment operation with respect to the cargo.
Management of these transitions has traditionally been approached by additional sling load sensors, camera optical aids, and other sensors. These solutions entail higher cost and multiple points of failure. Soft-weight-on-wheels algorithms have been suggested, however, such algorithms do not apply to slung load situations.